From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B75EC433F5 for ; Mon, 28 Mar 2022 15:43:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238529AbiC1Ppa (ORCPT ); Mon, 28 Mar 2022 11:45:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238368AbiC1PpZ (ORCPT ); Mon, 28 Mar 2022 11:45:25 -0400 Received: from mail-yb1-xb2c.google.com (mail-yb1-xb2c.google.com [IPv6:2607:f8b0:4864:20::b2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6E6C48395 for ; Mon, 28 Mar 2022 08:43:44 -0700 (PDT) Received: by mail-yb1-xb2c.google.com with SMTP id x20so26601034ybi.5 for ; Mon, 28 Mar 2022 08:43:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JLAMImTBODJ6p1BQ28mgm1zYhXSzYUbNlmQ348cuLdo=; b=GIYTLtunk/7VbdlxJz2L+F+hC5s7K7qDdgMJKyJ4TEI6TpypWEuW3uISWwVhgRmRe0 L6LGJ+vHPyfz+1A/Jo+JJKPbg5dJjRwKEq9Lp9sylO86h5+/W3mpm/Kt8HzHfDRSdZVx E6N8kncLZ6ofsBbax1zxIM7Bnm3vnPrReCA3DePBTNMu5wBShS4HbsbK/ta1/YWSKJZ0 3USyelDXZnfONkjzwyxvkcVd8DqqfxjXKo3qIeOx+eD6o+ITHJrCGnv6KnGg4fKwkaR+ epyweFbyBMws3SiH3/Az2m5+5iAkEu0t+ZWOGGeaKmiWLmc7a1kImsNi87Lj7qDjkfdX +CRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JLAMImTBODJ6p1BQ28mgm1zYhXSzYUbNlmQ348cuLdo=; b=gKUfViQPoOjb3IirIHr2FSvVsxfPfWdRylcmu0DrD8FCFW9T4LJfsOufQ4USyfSeJG R69DZ5TYg8U63r89H2c36WhUe/XSzUr/l5c5nbRPdLiDZ6SXWyWjiWAJy9iO18LZKnCO f1Rdbv54Dt0Vge+KpHm9T1k59QV/B9moxHuURPTCbTpLuUPDP/N3vlk4xhWnd8sM48md xc1SYsBi5W9DCy6qXmVPkWBkyAGiBWDrGhK5GlZo7ItpioVaFYVpPcWgPmw9FPjywgeF 4Pdu7uNEJNtzQSykV0k3RYiJrswT30o7pPf2QS4jTqP6eIi6NZTpo8H8oUpTfdx0UF0L 9a4w== X-Gm-Message-State: AOAM531k6ovh01WboeoJs1VkRBinfDWTrw3+ClE61T8NNruikarvDNZm bHWzCl4hLF9MYsuKRW/hoQOUje4PGA8AMcE7E2vUoy9ynaa01w== X-Google-Smtp-Source: ABdhPJwmVXEqdR8lQkP19/L8e0cirz16e509iPdj4QWD1qSuTNtPHrKLywy+HWYdoSO5gRqUetj/qXfwkm9pxb46L88= X-Received: by 2002:a05:6902:24f:b0:62d:69d:c9fc with SMTP id k15-20020a056902024f00b0062d069dc9fcmr22422814ybs.87.1648482223855; Mon, 28 Mar 2022 08:43:43 -0700 (PDT) MIME-Version: 1.0 References: <20220328132843.16624-1-songmuchun@bytedance.com> In-Reply-To: <20220328132843.16624-1-songmuchun@bytedance.com> From: Marco Elver Date: Mon, 28 Mar 2022 17:43:07 +0200 Message-ID: Subject: Re: [PATCH v2] mm: kfence: fix objcgs vector allocation To: Muchun Song Cc: glider@google.com, dvyukov@google.com, akpm@linux-foundation.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, duanxiongchun@bytedance.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 28 Mar 2022 at 15:28, Muchun Song wrote: > > If the kfence object is allocated to be used for objects vector, then > this slot of the pool eventually being occupied permanently since > the vector is never freed. The solutions could be 1) freeing vector > when the kfence object is freed or 2) allocating all vectors statically. > Since the memory consumption of object vectors is low, it is better to > chose 2) to fix the issue and it is also can reduce overhead of vectors > allocating in the future. > > Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB") > Signed-off-by: Muchun Song Reviewed-by: Marco Elver Btw, how did you test this? Thanks, -- Marco > --- > v2: > - Fix compiler error reported by kernel test robot . > > mm/kfence/core.c | 11 ++++++++++- > mm/kfence/kfence.h | 3 +++ > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 13128fa13062..d4c7978cd75e 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -555,6 +555,8 @@ static bool __init kfence_init_pool(void) > * enters __slab_free() slow-path. > */ > for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { > + struct slab *slab = page_slab(&pages[i]); > + > if (!i || (i % 2)) > continue; > > @@ -562,7 +564,11 @@ static bool __init kfence_init_pool(void) > if (WARN_ON(compound_head(&pages[i]) != &pages[i])) > goto err; > > - __SetPageSlab(&pages[i]); > + __folio_set_slab(slab_folio(slab)); > +#ifdef CONFIG_MEMCG > + slab->memcg_data = (unsigned long)&kfence_metadata[i / 2 - 1].objcg | > + MEMCG_DATA_OBJCGS; > +#endif > } > > /* > @@ -938,6 +944,9 @@ void __kfence_free(void *addr) > { > struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr); > > +#ifdef CONFIG_MEMCG > + KFENCE_WARN_ON(meta->objcg); > +#endif > /* > * If the objects of the cache are SLAB_TYPESAFE_BY_RCU, defer freeing > * the object, as the object page may be recycled for other-typed > diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h > index 2a2d5de9d379..9a6c4b1b12a8 100644 > --- a/mm/kfence/kfence.h > +++ b/mm/kfence/kfence.h > @@ -89,6 +89,9 @@ struct kfence_metadata { > struct kfence_track free_track; > /* For updating alloc_covered on frees. */ > u32 alloc_stack_hash; > +#ifdef CONFIG_MEMCG > + struct obj_cgroup *objcg; > +#endif > }; > > extern struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS]; > -- > 2.11.0 >